San Francisco Tides

Time Event Value Units
01:11 am High Tide 6.6 ft
02:01 am Slack
05:43 am Max Ebb -4.7 kt
08:10 am Low Tide -1.58 ft
10:24 am Slack
01:19 pm Max Flood 2.9 kt
03:36 pm High Tide 4.65 ft
04:36 pm Slack
07:07 pm Max Ebb -2 kt
07:54 pm Low Tide 2.9 ft
09:55 pm Slack
What day is the longest?
Why are there 2 tides per day?
Why doesn't Slack = High/Low Tide?
Why can you ride a flood but not an ebb?